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    <script>
        var a = 10;
        ++a;        //11
        var b = ++a + 2; //++a=11+1  14
        console.log(b); //14

        var c = 10;
        c++; //11
        var d = c++ + 2; // c++ = 11 c= 12  13
        console.log(d);  //13

        var e=10;   
        var f = e++ + ++e;  //  e++=10  e=11  e=12 e++=12 
        console.log(f); //22
    </script>
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